A novel hybrid quasi-solid polymer electrolyte based on porous PVB and modified PEG for electrochromic application

Accepted Manuscript A novel hybrid quasi-solid polymer electrolyte based on porous PVB and modified PEG for electrochromic application Wenjing Wang, Shian Guan, Mei Li, Jianming Zheng, Chunye Xu PII:

S1566-1199(18)30035-1

DOI:

10.1016/j.orgel.2018.01.035

Reference:

ORGELE 4507

To appear in:

Organic Electronics

Received Date: 5 October 2017 Revised Date:

25 January 2018

Accepted Date: 25 January 2018

Please cite this article as: W. Wang, S. Guan, M. Li, J. Zheng, C. Xu, A novel hybrid quasi-solid polymer electrolyte based on porous PVB and modified PEG for electrochromic application, Organic Electronics (2018), doi: 10.1016/j.orgel.2018.01.035. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT

SC

RI PT

Graphical Abstract

AC C

EP

TE D

M AN U

We first constructed hybrid QSPE (PVB and mPEG) to achieve high bond stress and long life in solid electrochromic devices.

ACCEPTED MANUSCRIPT

A Novel Hybrid Quasi-solid Polymer Electrolyte Based on Porous PVB and Modified PEG for Electrochromic

RI PT

Application

AC C

EP

TE D

M AN U

SC

Wenjing Wang, Shian Guan, Mei Li, Jianming Zheng*, Chunye Xu*

*Corresponding Authors *E-mail: [email protected] (J. Zheng), [email protected] (C. Xu) Address: Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026, P.R. 1

ACCEPTED MANUSCRIPT China Abstract: Hybrid quasi-solid polymer electrolytes (QSPEs) were obtained by adding modified polyethylene glycol (mPEG) prepolymer into porous polyvinyl butyral (PVB). The prepared QSPEs have good luminous clarity (transmittance >70% in the

RI PT

visible region), high ionic conductivity in the level of 10-5 S cm-1. On the other hand, bond stress of the QSPE reaches 0.57 fold increase with introduction of 12 wt. % PVB, attributing to functional groups in PVB. Moreover, an electrochromic device (ECD) was fabricated using PProDOT-Me2 and Li-Ti doped NiO as working and

SC

counter electrode respectively, and hybrid QSPE as electrolyte. Compared with ECD based on mPEG electrolyte, the ECD shows 43.81% of optical modulation (∆T) at

M AN U

585 nm, and maintains 84% of the initial ∆T value after 20,000 cycles. These outstanding comprehensive performances demonstrate the QSPE has extensive prospects for electrochromic applications.

1. Introduction

TE D

Keywords: hybrid electrolyte, bond stress, stability, electrochromic, device

Electrochromic devices (ECDs), which could show an optical transmittance change

EP

reversibly under external voltage[1-5], has been applied in various fields, such as smart windows, optical displays, and rearview mirrors[6-9]. A typical ECD consists of

AC C

five functional layers, an ion conductor layer sandwiched by an electrochromic (EC) layer and an ion-storage layer that are individually deposited on transparent electrodes[6].

Especially, solid polymer electrolyte (SPE) affects ionic conductivity, cycle durability and possesses good security which avoids electrolyte leaking compared with liquid electrolyte[10-17]. To study the physicochemical properties of SPE, researchers focused on changing inner structures by doping, introducing different host polymer, exploring interfacial effects between different components among electrolyte and so on[18-24]. Ganesh et al. reported SPEs on the basis of polymethyl methacrylate 2

ACCEPTED MANUSCRIPT (PMMA) with high ionic conductivity (10-4 S cm-1)[24]. Polymeric electrolytes achieved ionic conductivity of 2×10-4 S cm-1 and was cycled for 1,000 times by introducing titanium isopropoxide into an acidic polyethylene glycol (PEG)[23]. In 2017, glycerol as the plasticizer in polyvinyl alcohol and a nanocrystalline porous

RI PT

TiO2 buffer were employed to address degradation of device, which improved cycle stability of ECD from 100 to 1,000 cycles.

However, few work has been reported by combining porous viscous polymer and high conductivity material to solve the problem of cycle durability and ionic conductivity.

SC

In this work, a new hybrid quasi-solid polymer electrolyte (QSPE, one kind of SPEs) was first obtained by introducing porous polyvinyl butyral (PVB) into modified

M AN U

polyethylene glycol prepolymer[25]. The reason of introducing PVB into electrolyte is to enhance interfacial bond stress in the electrolyte, and cycle durability could be improved attributing to the strong bonding between electrolyte and substrates[26]. PVB is used in hybrid QSPEs for its high bond stress, because it has many advantages in practical applications. For instance, it has good aging resistance and outstanding

TE D

adhesion to glass, which is mainly used in safety glass laminates. This hybrid QSPE based on porous PVB and mPEG could keep ionic conductivity at high level and more

EP

importantly, improve its cycle durability.

2. Experimental Section

2.1. Materials and instruments

AC C

All solvents and chemicals were analytical grade and used without further purification. All materials, solvents and catalysts were purchased from Sinopharm Chemical Reagent Co. Ltd except for 2-hydroxyethyl acrylate (HEA, 97%), polyethylene glycol (PEG, Mw=1,000 g/mol), which were purchased from Aladdin Industrial Inc. The monomer 3,4-(2,2-dimethylpropy-lenedioxy) thiophene (ProDOT-Me2) was gained through approach reported by Xu et al.[27, 28]. Scanning electron microscopy (SEM), and Energy dispersive X-ray spectrometry (EDX) (Sirion 200, FEI, Hillsboro, Oregon, USA) were used to observe the 3

ACCEPTED MANUSCRIPT morphology of electrolyte and distribution of elements. Mercury intrusion porosimetry was measured by Pore Master 60, Quantachrome. An UV-vis-NIR spectrophotometer (V-670, JASCO, Tokyo, Japan) was chosen to investigate optical properties of ECDs. All electrochemical experiments including electrochemical

RI PT

impedance spectroscopy (EIS), cyclic voltammetry (CV), and cycle stability characterization were performed using an electrochemical workstation (CHI 650D, Chenhua, Shanghai, China). The linear-torsion all-electric dynamic test instrument (E3000, INSTRON, USA) was used to carry out bond stress characterization of

SC

QSPEs. 2.2. Preparation of porous PVB film and modified mPEG

M AN U

Powdered PVB of different concentrations (7 wt. %, 12 wt. %, 17 wt. %) was added into the solution of tetrahydrofuran (THF): dimethyl sulfoxide (DMSO)=9:1 (v/v), after stirring for 5 h and spun on indium tin oxide (ITO) glass (~9.0 Ω sq-1) evenly or counter electrode under the condition of 1,000 rpm and 20 s. Then the films were heated in a vacuum oven at 45°C for 15 min to remove THF, resulting in porous films.

TE D

To graft functional groups on PEG and copolymerize with methyl methacrylate (MMA), polyaddition reaction between isocyanates and hydroxyl groups was used to graft unsaturated functional groups at the hydroxyl end of PEG. Isophorone

EP

diisocyanate (IPDI) mixed with MMA was reacted with 2-hydroxyethyl acrylate (HEA) and PEG under catalysis of dibutyltin dilaurate (DBTDL) generating colorless or yellowish viscous liquid. After adding photocuring agent, modified PEG electrolyte

AC C

(mPEG) as contrast was gained by mixing 60 wt. % 0.1 M LiClO4 in propylene carbonate (PC) and 40 wt. % viscous liquid. 30 wt. % 0.1 M LiClO4/PC, 50 wt. % ACN and 20 wt. % viscous liquid was mixed to obtained mPEG prepolymer and it was filled into porous PVB. Specific reaction process and characterization is described in Supporting Information. 2.3. Preparation of working electrode and counter electrode The poly 3,4-(2,2-dimethylpropylenedioxy) thiophene (PProDOT-Me2) film was electropolymerized onto the surface of ITO glass (~9.0 Ω sq-1) in the solution of 0.1 4

ACCEPTED MANUSCRIPT M LiClO4 and 0.01 M ProDOT-Me2 monomer in acetonitrile, using a three-electrode system. The three-electrode system contained silver wire as reference electrode and a platinum sheet as counter electrode. PProDOT-Me2 was electropolymerized on ITO at

RI PT

1.65 V (vs. Ag/Ag+) for 5 s with chronoamperometry[3]. Li-Ti-NiO counter electrode was prepared with the method of sol–gel spin coating according to Zhou et al.[6]. 2.4. Construction of hybrid QSPEs and assembly of QSPE-ECD

Firstly, a piece of porous PVB (7 wt. %, 12 wt. %, 17 wt. %) film based on Li-Ti-NiO

SC

electrode (1.72×3.45 cm2) was dripped with mPEG prepolymer and evacuated in a vacuum oven to make mPEG prepolymer fill into the micropores at room temperature

M AN U

for 30 min. Heating at 45°C in the vacuum to remove redundant ACN is necessary. Secondly, a parafilm (100 µm thickness) was cast onto PProDOT-Me2 electrode and fabricated together with prepared Li-Ti-NiO electrode. The parafilm was employed as a spacer to control thickness of modified PEG in QSPEs. In addition, the ECD was evacuated in a vacuum oven at room temperature for 30 min to remove ACN slowly

TE D

and evacuated at 45°C for 30 min to remove ACN completely. Finally, the QSPE-ECD (quasi-solid polymer electrolyte-electrochromic device) was cured by UV lamp for 20 min and heated at 120°C for 2 h to make PVB become sticky by melting,

EP

and the thickness of QSPE-ECD was controlled by solid modified PEG. Schematic of electrochromic device as well as flow diagram of assembling ECD and sandwich

AC C

structure are shown in Fig. 1 and Fig. 2, respectively. 2.5. Optical and electrochemical characterization of electrolyte Bond stress characterization were performed in ECDs with 1.8 mm thick ITO (~9.0 Ω sq-1). The assembly of sandwich structures for EIS and transmittance characterization is very similar to the assembly of ECDs. All of them employed the same QSPEs, and the difference is that working and counter electrode were replaced by two pure 1.72×3.45 cm2 ITO glasses. The way of processing and assembly is the same. Therefore, sandwich structures based on PVB (7%)-mPEG, PVB (12%)-mPEG, PVB (17%)-mPEG were prepared. 5

ACCEPTED MANUSCRIPT

3. Results and Discussion 3.1. Morphology and structure of porous PVB film and hybrid QSPEs Fig. 3 shows surface and cross-sectional SEM images of PVB films in a concentration

RI PT

of 7 wt. %, 12 wt. % and 17 wt. %, respectively. After vacuum treatment of spin-coating PVB film, porous structure can be observed in all of films surface for strong volatility of THF in solution[18, 29]. As PVB concentration increases from 7 wt. % to 17 wt. %, average diameter of pore improves from 0.17 µm to 2.7 µm, then

SC

decreases to 1.8 µm as collected in Table 1[6]. The pore size increases to the maximum until the concentration of PVB reaches to 12 wt. %, which is related to

M AN U

concentration and aggregation of polymer[29, 30]. Thickness increases from 3.1 µm to 17.3 µm for improving concentration. Thus, 12 wt. % PVB films shows the largest pore size, which would be easier to be filled into pores by modified PEG (mPEG). Then, mercury intrusion porosimetry was employed to measure porosity[31-33]. Same change as the above, total porosity of film increases from 5.50% to 7.45%, then

TE D

dramatically decreases to 5.46% (Table 1). In summary, 12 wt. % PVB gets the highest total porosity, which is consistent with surface morphology analysis[34, 35]. Therefore, changing concentration of PVB solution can not only control morphology,

EP

but also affect its porosity. Larger porosity is beneficial for ions to transfer in the electrolyte, which will greatly improve response time for the device. In order to demonstrate that mPEG prepolymer could enter into porous PVB film,

AC C

EDX maps were provided to reveal distribution of mPEG prepolymer[25, 29, 36-38]. Since both of PVB film and mPEG prepolymer have same element composition, element Cl (from lithium perchlorate) was added into mPEG prepolymer as a mark to verify whether element mPEG prepolymer entered into porous PVB film or not[39]. Fig. 4 displays SEM images of porous PVB film (a) and hybrid QSPEs (d), as well as corresponding EDX maps with different elementals. The presence of element C demonstrates that both samples are carbon-containing compounds, i.e., PVB and hybrid PVB-mPEG. It is clear that cross section of the QSPE is enriched with 6

ACCEPTED MANUSCRIPT elemental Cl, which proves mPEG prepolymer is filled into porous PVB film evenly.

3.2. Optical, electrochemical and adhesive properties of hybrid QSPEs 3.2.1 Optical transmittance analysis

RI PT

Fig.5 shows photos (inset) and transmittance curves in 300-1800 nm for mPEG and different QSPEs. QSPE consists of PVB and mPEG, which both are relatively transparent material in SPE area. It reveals that hybrid QSPEs and mPEG electrolyte reach more than 70% of transmittance in the visible region (400-800 nm). According

SC

to results of optical transmittance spectra, hybrid QSPEs are favorable for application

M AN U

of ECDs.

3.2.2 Electrochemical impedance spectroscopy analysis

To characterize conductive behavior of electrolytes, electrochemical impedance spectroscopy (EIS) was performed with “ITO glass/electrolyte/ITO glass” structure at a constant potential of +0.5 V in the frequency range of 10-2-105 Hz. Fig. 6 shows

TE D

Nyquist plots of electrolytes employed with different concentrations of PVB. An equivalent circuit (Fig. S4) was applied in the process of fitting experimental results using a non-linear least squares fitting minimization method with the Zsimpwin

EP

program. The Nyquist plots for mPEG electrolyte (Fig. 6a) and QSPEs with different concentrations of PVB (Fig. 6b, c and d) are presented, where the line with square ( ) represents measured data, while the line with circle ( ) represents the simulating data

AC C

using equivalent circuit (Fig. S4). The chart consists of partially overlapped semicircle in the high frequency scope and a straight slopping line at low-frequency end. The ionic conductivity can be computed using Eq. (1)

σ =

d Rb × A

(1)

where Rb is obtained from the simulating data using ZSimpwin software, A is the area of the electrolyte, d is the thickness of electrolyte [3, 11, 40]. All the calculated values 7

ACCEPTED MANUSCRIPT of ionic conductivity are collected in Table 2. With PVB content increases from 0 to 17 wt. %, the ionic conductivity decreases from 0.0963 to 0.0019 mS cm-1. Meantime, as shown in Fig.7, diffusion coefficients of mPEG and QSPEs were also calculated by inclined line in the low-frequency region of EIS curves by the following

DLi + =

RI PT

Eq. (2)

R2T 2 2A2n 4F 4C2δw2

(2)

where A is the surface area of electrode, n is the number of electrons per molecule

SC

participating the electronic transfer reaction[35, 41], F is Faraday constant (96,485 C mol−1), R is gas constant (8.3143 J mol−1 K−1), T is absolute temperature (298 K), C is

M AN U

the concentration of lithium ions in electrolyte, and δω is the Warburg factor which can be obtained by the following equation:

Z = R s + R ct + δw ω 1 / 2

(3)

In Equation (3), Z′ is the real part of impedance, ω represents angular frequency. Fig. 7 shows linear relationship of Z′ and ω1/2 in different electrolytes. According to

TE D

equations (1) and (2), DLi+ values are calculated and recorded in Table 2. DLi+ values are in the level of 10-19 cm2 s-1 and decrease from 4.247×10-19 to 1.085×10-19 cm2 s-1 with increasing PVB content, which is consistent with ionic conductivity results. The

EP

higher ionic conductivity and diffusion coefficient suggests the easier Li+ and [ClO4]mobility. Therefore, QSPEs with better comprehensive properties between ionic conductivity and mechanical strength need to be found accompanied by the

AC C

introduction of PVB.

3.2.3 Adhesive properties Bond stress refers to the applied load (or tension) per area to make it separated from the substrate in the adhesive portion[42, 43]. Here, PVB traditionally used in safety glass was introduced into mPEG electrolyte to improve its mechanical strength. Bond stress

tests

were

performed

in

ECD

structure

(ITO

glass/PProDOT-Me2/electrolyte/Li-Ti- NiO/ITO glass, the glass is 1.8 mm thick) to 8

ACCEPTED MANUSCRIPT simulate actual application environment. PVB concentration effects on bond stress of hybrid QSPEs are shown in Fig. 8a. The mPEG electrolyte reaches 0.14 Mpa of bond stress in ECD. Due to the increase of PVB concentration, bond stress of hybrid QSPE improves from 0.20 Mpa to 0.37 Mpa

RI PT

in the range of 7-17 wt. % as illustrated in Fig. 8a. Especially, adding 12 wt. % PVB to electrolyte improves bond stress by 0.57 fold compared with mPEG electrolyte (from 0.14 Mpa to 0.22 Mpa). PVB is endowed with extremely high adhesion for its hydroxyl, butyral groups and unreacted acetate groups. Functional groups could

SC

combine hydroxyl of mPEG. Considering analysis of EIS and bond stress integration diagram (Fig. 8b), there is an intersection at PVB concentration of 12 wt. %, which

M AN U

suggests the hybrid QSPE with 12 wt. % PVB gains better comprehensive properties with ionic conductivity of 0.0487 mS cm-1 and bond stress of 0.22 Mpa.

3.3 Performance of electrochromic device with hybrid QSPEs The prepared PProDOT-Me2 electrode, Li-Ti-NiO electrode and porous PVB

TE D

(12%)-mPEG electrolyte were employed to fabricate a QSPE-ECD. An mPEG-ECD was set as contrast with same working electrode and counter electrode. Fig. 9 shows photos of colored and bleached state of ECDs based on mPEG

EP

electrolyte and the hybrid QSPE with 12 wt. % PVB. At -1.8 V, two ECDs changed to colored state showing a deep blue color, accompanied by PProDOT-Me2 returned to their reduced states. At 2 V, two ECDs became transparent immediately, meantime

AC C

PProDOT-Me2 transformed to their oxidized states. As illustrated in Fig. 9c, over 55% transmittance in the main range of visible region (400-800 nm) can be achieved in both bleached states. Also, two ECDs demonstrate low spectra absorption around 20% transmittance in colored state. The percentage transmittance change (∆T) at a specific wavelength is determined by the equation ∆T= Tbleach–Tcolor (Tbleach and Tcolor are transmittance in the fully bleached and fully colored states, respectively). Being applied with -1.8 V and +2 V for 5 s using chronocoulometry program, the QSPE-ECD switches from colored state to bleached state in low voltage, as well as 9

ACCEPTED MANUSCRIPT achieves a relatively satisfactory optical contrast of 43.81% at 585 nm. Response time of ECD is a very significant parameter for electrochromic applications (Fig. 10). Response time is defined as needed time of ECD to realize 90% of its optical modulation at a specific wavelength. Referring to related literature about

RI PT

applied voltage of PProDOT-Me2 electrode, -1.8 V was chose for coloring and 2.0 V for bleaching[44-46]. As shown in Fig. 10, response time of hybrid QSPE-ECD (tb=2.6 s, tc=1.2 s) is slightly longer than that of mPEG-ECD (tb=2.7 s, tc=0.8 s) in the coloring process. With PProDOT-Me2 as working electrode, response time of ECD is

SC

influenced by diffusion rate of Li+ dissolved in the electrolyte and amount of electron entering into PProDOT-Me2. PEG-based SPEs have strong ionic conductivity because

M AN U

of many ion transport channels, while PVB shows weaker ionic conductivity[47, 48]. Therefore, mPEG filler ensure fast switching property of QSPE despite introducing pore PVB.

Long-term stability of QSPE also plays a critical role in the future electrochromic applications. Electrochemical stability of QSPE-ECD was researched using

TE D

multi-voltage-step method, which was switched between -1.8 V (5 s) and 2.0 V (5 s) for 20,000 cycles. Transmittance at 585 nm after different cycles was also recorded. mPEG-ECD was investigated cycle stability at the same voltage and time, which is as

EP

contrast to research effect of adding PVB.

As proved in Fig. 11a and b, an mPEG-ECD was carried out for 6,000 cycles with contrast loss of 9.62% (from 35.72% to 26.10%). A QSPE-ECD demonstrates a good

AC C

stability over 20,000 switching cycles, accompanied by an optical modulation loss of 7.18% (from 43.81% to 36.63%) as shown in Fig. 11c and d. Increase of long term stability in QSPE-ECD is attributed to PVB viscous skeleton structure, which keeps solid polymer electrolyte in a relatively stable structure during ion transport and further improves life of ECD. Thus, fabricated QSPE-ECD exhibits stable high optical modulation even after 20,000 switchings, showing promising prospect for future use in electrochromic devices.

10

ACCEPTED MANUSCRIPT Conclusions In this paper, hybrid QSPEs based on porous PVB and mPEG prepolymer were obtained. First, results demonstrate that QSPEs possess high transmittance (>70% in the visible region) and high ionic conductivity in the level of 10-5 S cm-1. Then, bond

RI PT

stress of the QSPE reaches 0.57 fold increase based on PVB (12%)-mPEG, attributing to strong adhesive property of PVB functional groups. Moreover, QSPE-ECD possesses a relative high ∆T of 43.81% at 585 nm, with its color switches from blue to transparent state. The device achieves fast switching between colored and bleached

SC

state (tc=1.2 s, tb=2.6 s), which documents doped PVB does not affect response time of device. In addition, as introduction of PVB makes electrolyte more robust and

M AN U

facilitates ion mobility, QSPE-ECD shows 43.81% of optical modulation (∆T) at 585 nm, and keeps 84% of the initial ∆T value after 20,000 cycles. Results indicate that the QSPE with porous PVB and mPEG has broad implemented prospects in smart windows and anti-glare mirrors et al.

TE D

Acknowledgements

This study was supported by the Fundamental Research Funds for the Central Universities (WK6030000047) and the National Natural Science Foundation of China

AC C

References

EP

(21774114 and 51503193).

[1] V.K. Thakur, G. Ding, J. Ma, P.S. Lee, X. Lu, Hybrid materials and polymer electrolytes for electrochromic device applications, Adv. Mater. 24 (2012) 4071-4096. [2] A.M. Osterholm, D.E. Shen, J.A. Kerszulis, R.H. Bulloch, M. Kuepfert, A.L. Dyer, J.R. Reynolds, Four shades of brown: tuning of electrochromic polymer blends toward high-contrast eyewear, ACS Appl. Mater. Interfaces 7 (2015) 1413-1421. [3] S. Guan, A.S. Elmezayyen, F. Zhang, J. Zheng, C. Xu, Deterioration mechanism of electrochromic poly(3,4-(2,2-dimethylpropylenedioxy)thiophene) thin films, J. Mater. Chem. C 4 (2016) 4584-4591. [4] D. Corr, Coloured electrochromic “paper-quality” displays based on modified mesoporous electrodes, Solid State Ionics, 165 (2003) 315-321. [5] P. Andersson Ersman, J. Kawahara, M. Berggren, Printed passive matrix addressed electrochromic displays, Org. Electron. 14 (2013) 3371-3378.

11

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

[6] J. Zhou, Y. Wei, G. Luo, J. Zheng, C. Xu, Electrochromic properties of vertically aligned Ni-doped WO3 nanostructure films and their application in complementary electrochromic devices, J. Mater. Chem. C, 4 (2016) 1613-1622. [7] S.-M. Wang, L. Liu, W.-L. Chen, E.-B. Wang, High performance visible and near-infrared region electrochromic smart windows based on the different structures of polyoxometalates, Electrochim. Acta 113 (2013) 240-247. [8] P.R. Somani, S. Radhakrishnan, Electrochromic materials and devices present and future. Mater. Chem. Phys. 77 (2002) 117-133. [9] D.R. Rosseinsky, R.J. Mortimer, Electrochromic systems and the prospectsfor devices. Adv. Mater. 13 (2001) 783-792. [10] L. Wang, Z. Huo, L. Tao, J. Zhu, C. Zhang, S. Chen, S. Dai, Quasi-solid-state dye-sensitized solar cell based on gel electrolyte with high gel to solution transition temperature using low molecular mass organogelator, J. Photochem. Photobiol., A 329 (2016) 139-145. [11] D. Sygkridou, A. Rapsomanikis, E. Stathatos, Functional transparent quasi-solid state dye-sensitized solar cells made with different oligomer organic/inorganic hybrid electrolytes, Sol. Energy Mater. Sol. Cells 159 (2017) 600-607. [12] A.A. Solovyev, A.N. Zakharov, S.V. Rabotkin, N.F. Kovsharov, Electrochromic device with polymer electrolyte, J. Electron. Mater. 45 (2016) 3866-3871. [13] J. Mindemark, L. Imholt, J. Montero, D. Brandell, Allyl ethers as combined plasticizing and crosslinkable side groups in polycarbonate-based polymer electrolytes for solid-state Li batteries, J. Polym. Sci., Part A: Polym. Chem. 54 (2016) 2128-2135. [14] Q. Liu, G. Dong, Y. Xiao, M.-P. Delplancke-Ogletree, F. Reniers, X. Diao, Electrolytes-relevant cyclic durability of nickel oxide thin films as an ion-storage layer in an all-solid-state complementary electrochromic device, Sol. Energy Mater. Sol. Cells 157 (2016) 844-852. [15] U. León-Silva, M.E. Nicho, H. Hu, Comparative study of optical kinetics in single and dual poly3-methylthiophene-based solid electrochromic devices, J. Solid State Electrochem. 12 (2007) 71-80. [16] S. Gomari, I. Ghasemi, M. Esfandeh, Effect of polyethylene glycol-grafted graphene on the non-isothermal crystallization kinetics of poly(ethylene oxide) and poly(ethylene oxide):lithium perchlorate electrolyte systems, Mater. Res. Bull. 83 (2016) 24-34. [17] L.M.N. Assis, J.R. Andrade, L.H.E. Santos, A.J. Motheo, B. Hajduk, M. Łapkowski, A. Pawlicka, Spectroscopic and microscopic study of Prussian blue film for electrochromic device application, Electrochim. Acta 175 (2015) 176-183. [18] J. Wang, The interfacial effects on the conductive performance of the composite films based on materials with electron and ionic conductors, Compos. Interfaces 20 (2013) 661-671. [19] D. Saikia, Y.-C. Pan, C.-G. Wu, J. Fang, L.-D. Tsai, H.-M. Kao, Synthesis and characterization of a highly conductive organic–inorganic hybrid polymer electrolyte based on amine terminated triblock polyethers and its application in electrochromic devices, J. Mater. Chem. C, 2 (2014) 331-343. [20] S.A. Agnihotry, Pradeep, S.S. Sekhon, PMMA based gel electrolyte for EC smart windows. Electrochim. Acta 44(1999) 3121-3126.

12

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

[21] R. Ramadan, H. Kamal, H.M. Hashem, K. Abdel-Hady, Gelatin-based solid electrolyte releasing Li+ for smart window applications, Sol. Energy Mater. Sol. Cells 127 (2014) 147-156. [22] N. Mendoza, F. Paraguay-Delgado, L. Hechavarría, M.E. Nicho, H. Hu, Nanostructured polyethylene glycol–titanium oxide composites as solvent-free viscous electrolytes for electrochromic devices, Sol. Energy Mater. Sol. Cells 95 (2011) 2478-2484. [23] L. Hechavarría, N. Mendoza, P. Altuzar, H. Hu, In situ formation of polyethylene glycol– titanium complexes as solvent-free electrolytes for electrochromic device application, J. Solid State Electrochem. 14 (2009) 323-330. [24] G.P.T. Ganesh, R. Ravi, B. Deb, A pragmatic approach to methyl methacrylate based solid polymer electrolyte processing: A case study for electrochromism, Sol. Energy Mater. Sol. Cells 140 (2015) 17-24. [25] A.-l. Zhang, F.-y. Cao, G.-z. Na, S. Wang, S.-x. Li, J.-c. Liu, A novel PEO-based blends solid polymer electrolytes doping liquid crystalline ionomers, Ionics 22 (2016) 2103-2112. [26] G.P.T. Ganesh, B. Deb, Designing an all-solid-state Tungsten Oxide based electrochromic switch with a superior cycling efficiency, Adv. Mater. Interfaces 4 (2017) 1700124. [27] C.Y. Xu, H. Tamagawa, M.B. Uchida, M. Taya, Enhanced contrast ratios and rapid switching color changeable devices based on poly(3,4-propylenedioxythiophene) derivative and counterelectrode, Smart Structures and Materials, Proc. SPIE. 4695 (2002) 442-450. [28] C. Xu, L. Liu, S.E. Legenski, D. Ning, M. Taya, Switchable window based on electrochromic polymers, J. Mater. Res. 19 (2011) 2072-2080. [29] F.M. Ribeiro, E.R. Faria, R.M. Verly, D.V. Franco, L.M. Da Silva, Fabrication and characterisation of mixed oxide-covered mesh electrodes of nominal composition Ni(x)Co(1−x)Oy supported on stainless-steel prepared by thermal decomposition using the slow cooling rate method, Electrochim. Acta 194 (2016) 127-135. [30] Z. Li, H. Tang, X. Liu, Y. Xia, J. Jiang, Preparation and characterization of microporous poly(vinyl butyral) membranes by supercritical CO2-induced phase separation, J. Membr. Sci. 312 (2008) 115-124. [31] M. Han, J.H. Xu, S.H. Chan, S.P. Jiang, Characterization of gas diffusion layers for PEMFC, Electrochim. Acta 53 (2008) 5361-5367. [32] M.J. Martínez-Rodríguez, T. Cui, S. Shimpalee, S. Seraphin, B. Duong, J.W. Van Zee, Effect of microporous layer on MacMullin number of carbon paper gas diffusion layer, J. Power Sources 207 (2012) 91-100. [33] S. Ghosh, H. Ohashi, H. Tabata, Y. Hashimasa, T. Yamaguchi, Microstructural pore analysis of the catalyst layer in a polymer electrolyte membrane fuel cell: A combination of resin pore-filling and FIB/SEM, Int. J. Hydrogen Energy 40 (2015) 15663-15671. [34] X. Guo, Y. Zeng, Z. Wang, Z. Shao, B. Yi, Investigation of porous water transport plates used for the humidification of a membrane electrode assembly, J. Power Sources 302 (2016) 84-91. [35] A.T. Tesfaye, Y. Gogotsi, T. Djenizian, Tailoring the morphological properties of anodized Ti 3 SiC 2 for better power density of Li-ion microbatteries, Electrochem. Commun. 81 (2017) 29-33. [36] H. Xu, Z. Lu, S. Ukai, N. Oono, C. Liu, Effects of annealing temperature on nanoscale

13

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

particles in oxide dispersion strengthened Fe-15Cr alloy powders with Ti and Zr additions, J. Alloys Compd. 693 (2017) 177-187. [37] M. Shahbazi, A. Bahari, S. Ghasemi, Structural and frequency-dependent dielectric properties of PVP-SiO2-TMSPM hybrid thin films, Org. Electron. 32 (2016) 100-108. [38] Q. Feng, D. Tang, H. Lv, W. Zhang, W. Li, Surface-initiated ATRP to modify ZnO nanoparticles with poly(N-isopropylacrylamide): Temperature-controlled switching of photocatalysis, J. Alloys Compd. 691 (2017) 185-194. [39] Q. Zhao, G. Zhang, G. Xu, Y. Li, B. Liu, X. Gong, D. Zheng, J. Zhang, Q. Wang, Synthesis of highly active and dual-functional electrocatalysts for methanol oxidation and oxygen reduction reactions, Appl. Surf. Sci. 389 (2016) 181-189. [40] X. Qian, N. Gu, Z, Cheng, X. Yang, E. Wang, S. Dong, Methods to study the ionic conductivity of polymeric electrolytes using a.c. impedance spectroscopy, J. Solid State Electrochem. 6 (2001) 8-15. [41] X. Wang, Q. Cheng, T. Huang, A. Yu, Effect of calcination atmosphere on Li/Ni disorder and electrochemical performance of layered LiNi0.5Mn0.5O2, Acta Phys. ⁃Chim. Sin. 27 (2011) 437-442. [42] K.H. Mo, S.H. Goh, U.J. Alengaram, P. Visintin, M.Z. Jumaat, Mechanical, toughness, bond and durability-related properties of lightweight concrete reinforced with steel fibres, Mater. Struct. 50 (2016) 46. [43] C.A. Issa, J.J. Assaad, Stability and bond properties of polymer-modified self-consolidating concrete for repair applications, Mater. Struct. 50 (2016) 28. [44] M. Mallouki, P.-H. Aubert, L. Beouch, F. Vidal, C. Chevrot, Symmetrical electrochromic device from poly(3,4-(2,2-dimethylpropylenedioxy)thiophene)-based semi-interpenetrating polymer network, Synth. Met. 162 (2012) 1903-1911. [45] D.M. Welsh, A. Kumar, E.W. Meijer, and J.R. Reynolds, Enhanced contrast ratios and rapid switching in electrochromics based on poly(3,4-propylenedioxythiophene) derivatives, Adv. Mater. 11 (1999) 1379-1381. [46] E. Amasawa, N. Sasagawa, M. Kimura, M. Taya, Design of a new energy-harvesting electrochromic window based on an organic polymeric dye, a cobalt couple, and PProDOT-Me2, Adv. Energy Mater. 4 (2014) 1400379. [47] M. Guo, M. Zhang, D. He, J. Hu, X. Wang, C. Gong, X. Xie, Z. Xue, Comb-like solid polymer electrolyte based on polyethylene glycol-grafted sulfonated polyether ether ketone, Electrochim. Acta 255 (2017) 396-404. [48] S. Kim, M. Taya, C. Xu, Contrast, switching speed, and durability of V2O5–TiO2 film-based electrochromic windows, J. Electrochem. Soc. 156 (2009) E40-E45.

Figure Caption Figure 1. Schematic drawing of electrochromic device based on hybrid QSPE. Figure 2. Route diagram of fabricating electrochromic device and sandwich structure. Figure 3. Surface and cross section SEM images of different PVB films

(a) and (a′)

are for 7 wt. % PVB, (b) and (b′) belong to 12 wt. % PVB, (c) and (c′) are for 17 wt. % 14

ACCEPTED MANUSCRIPT PVB. Figure 4. EDX maps of hybrid QSPE: SEM image (a), element mapping of C (b) and Cl (c); EDX maps of porous PVB film: SEM image (d), element mapping of C (e) and Cl (f).

hybrid QSPE and mPEG electrolyte.

RI PT

Figure 5. Corresponding photographs and optical transmittance spectra of different

Figure 6. Nyquist plots of EIS data for mPEG electrolyte (a) and hybrid QSPE with different concentrations of PVB: (b) 7 wt. %, (c) 12 wt. % and (d) 17 wt. %.

SC

Figure 7. Plots of Z′ vs. ω1/2 with different electrolyte.

Figure 8. Bond stress-slip at free end relationship, integration diagram of conductivity

M AN U

and bond stress of different hybrid QSPE and mPEG electrolyte. Inset photo is an ECD example using for bond stress test with PVB (12%)-mPEG. Figure 9. Colored and bleached state photos of mPEG-ECD (a) and QSPE-ECD (b). (c) Optical transmittance spectra of ECD with mPEG electrolyte and PVB (12%)-mPEG at colored and bleached state (Lower line of hybrid QSPE at 585 nm is

TE D

for colored state, upper one belongs to its bleached state. Line classification of mPEG electrolyte is the same as above.).

Figure 10. Electrochromic response time of ECD at 585 nm (-1.8 V to color, 2 V to

EP

bleach) for mPEG electrolyte (blue line) and hybrid QSPE (black line, PVB (12%)-mPEG).

Figure 11. Optical transmittance of mPEG-ECD (a) and QSPE-ECD (c) at colored and

AC C

bleached state after different cycles, optical modulation at 585 nm of mPEG-ECD (b) and QSPE-ECD (d) with different cycle number. QSPE here is based on PVB (12%)-mPEG.

15

ACCEPTED MANUSCRIPT Table 1 Average thickness, pore diameter and total porosity of different porous PVB films. Thickness ( m)

Pore diameter ( m)

Total porosity (%)

7 wt. %PVB

3.1

0.17

5.50

12 wt. %PVB

9.5

2.7

7.45

17 wt. %PVB

17.3

1.8

RI PT

Porous PVB films

5.46

SC

Table 2 Ionic conductivity and diffusion coefficient of electrolytes with different concentration of PVB. Diffusion coefficient DLi+

M AN U

Different electrolytes

Ionic conductivity (mS cm-1)

(cm2 s-1)

0.0963

4.247×10-19

0.0654

1.921×10-19

PVB(12%)-mPEG hybrid QSPE

0.0487

1.443×10-19

PVB(17%)-mPEG hybrid QSPE

0.0019

1.085×10-19

mPEG electrolyte

AC C

EP

TE D

PVB(7%)-mPEG hybrid QSPE

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT

Highlights 1. New hybrid quasi-solid polymer electrolyte used in electrochromic device was obtained.

RI PT

2. Bond stress of hybrid electrolyte can reach 0.22 Mpa in electrochromic device. 3. Electrochromic device with hybrid electrolyte can exhibit excellent stability up to

AC C

EP

TE D

M AN U

SC

20,000 cycles.